It might be that the mesh is using the camera as a parent.
Otherwise, if you check your character Blueprint and look under the Defaults tab “Use Controller Rotation Yaw” will affect horizontal rotation while “Use Controller Rotation Pitch” will affect vertical rotation. These will affect the rotation of the whole mesh.
Failing that, you might need to offset the camera so it’s not intersecting the mesh. Depends what the specifics are, I had a few issues like it myself. I recommend checking out this video: - YouTube